The present invention relates to agents and methods for blocking deleterious T cell mediated immune reactions. Such reactions occur in autoimmune diseases, such as for example, multiple sclerosis (MS), rheumatoid arthritis, systemic lupus erythematosis, psoriasis, diabetes, and allergies. Such reactions also occur during rejection of transplants.
In theory, autoimmune diseases can be prevented by blocking activation of T cells and formation of autoreactive T cells. Accordingly, there are a number of studies being conducted to identify methods or agents that can be used to block activation of T cells (J Clin Invest. 1995 June; 95(6):2783-9; J Med. Chem. 2002 January 17; 45(2):275-83). Unfortunately, since patients with autoimmune diseases have already developed autoreactive T cells, these methods have limited value for treatment of autoimmune diseases. Moreover, agents that prevent systemic T cell activation often cause serious side effects. For example, treatment with agents that block activation of T cells can also render the patient more susceptible to infections and cancer. Thus, it is desirable to have new methods for treating autoimmune diseases. A method which reduces the destruction of targeted tissues that is initiated by autoreactive T cells is especially desirable.